A motor vehicle normally has three foot-operated pedals, a clutch pedal, a brake pedal and an accelerator. The driver operates the clutch pedal by his left foot and moves his right foot between the brake pedal and the accelerator. The controlling of the speed of the engine is effected by the driver placing his right heel on the floor of the vehicle and then turning the right foot forwards-downwards about the ankle joint. To brake the vehicle, the driver presses his right foot against the floor in the direction of the lower part of the leg.
A vehicle with automatic gear-change has no clutch pedal, but the controlling of the speed of the engine and braking must in any case, according to existing regulations, be carried out as described above, i.e. by moving the right foot between the brake pedal and the accelerator.
Above all in emergency braking, this multiple-pedal system causes elements of considerable risk. In an emergency, the stopping distance is prolonged owing to the time required for moving the right foot, and besides the moving of the foot involves a risk that the driver steps on the wrong pedal or slips on the brake pedal.
In order to obviate these elements of risk, various combined gas and brake pedals (single-pedal systems) have already been suggested, in which one tries to minimise the required movement of the right foot in an emergency.
SE 7604223-3 discloses a single-pedal system having a pivotally mounted pedal holder, which supports a pedal, which is pivoted to a shaft which is arranged on the pedal holder and extends perpendicular to the pivoting plane of the pedal holder. The speed of the engine and normal braking are controlled by means of mutually opposed pedal movements about said shaft. The speed of the engine is increased by turning the right foot forwards about the ankle joint, and normal braking takes place by an opposed turning backwards of the right foot. During these movements of the foot, the pedal holder is actuated by a spring means towards a resting position. The pedal holder is arranged in such a manner that emergency braking of the vehicle can be carried out by a relatively powerful pressing-down of the pedal in the direction of the lower part of the leg, whereby the pedal holder moves away from the resting position in the direction of the lower part of the leg. After the emergency braking, the pedal holder is returned to its resting position by the spring means.
The single-pedal system according to SE 7604223-3, however, suffers from a number of drawbacks, in particular:
The driver cannot operate the pedals in conventional manner. Normal braking takes place in a manner which is completely new to the driver--turning of the foot upwards about the ankle joint. What makes matters worse is that emergency braking is carried out in a different manner. When the user has finally got used to this new manner of braking normally, the practised reflex of pressing the brake pedal in the direction of the lower part of the leg in an emergency is deteriorated. Admittedly, the system may theoretically result in shorter reaction times compared with a conventional multiple-pedal system, but in practice the reaction times will probably be considerable since the movement for emergency braking no longer conforms with the movement for normal braking of the system and therefore is not made by instinct. PA1 A comparatively long learning time for the driver to function, if at all possible, in a reliable manner. Moreover, difficulties and risks will probably arise when changing to a car having a conventional multiple-pedal system. PA1 Since the spring means produces an increasing resistance as the pedal is pressed down in the direction of the lower part of the leg, this single pedal system results in a considerably deteriorated pedal pressure in case of an emergency braking. When the pedal pressure is urgently needed, it is thus reduced by the spring means which counteracts the emergency braking motion. PA1 Moreover, it would probably be difficult to introduce this prior-art single-pedal system on the market since the user must adapt himself to the pedals and not the opposite. PA1 The single-pedal system also requires relatively great modifications when installing it an existing vehicle. It will thus be expensive and complicated to exchange existing, conventional multiple-pedal systems for this single-pedal system.
EP-A-0 522 556 discloses a pedal system having separate gas and brake pedals, which, however, are arranged in such manner that they can be operated by the driver's one foot. A separate brake pedal, when not loaded by the driver's foot, is kept in a resting position by means of two cooperating permanent magnets. A separate turnable accelerator is arranged above the brake pedal. The speed of the engine is controlled by turning the accelerator sideways while holding the heel against the floor. Both normal braking and emergency braking are carried out by the driver turning his foot forwards-downwards about the ankle joint. Also this known pedal system thus requires movement patterns which are completely different from conventional multiple-pedal systems and thus involves the above-mentioned drawbacks.